Titanium Grade 5 / 6Al4V

Titanium Grade 5 has good tensile properties at ambient temperature and a useful creep resistance up to 300oC (570oF). Resistance to fatigue and crack propagation is excellent. Like most titanium alloys, Grade 5 has outstanding resistance to corrosion in most natural and many industrial process environments.

 Chemical Composition Titanium Grade 5 / 6Al4V

Applications of Titanium Grade 5 / 6Al4V

Titanium Grade 5 is a pure alpha-beta titanium with aluminium as the alpha stabilizer and vanadium as the beta stabilizer. This alloy is primarily used for corrosion resistance and is the most widely used specification in all product forms. The alloy features very high strength, good corrosion resistance, excellent strength-to-weight ratio and high strength at cryogenic temperatures.

Physical Properties

 Titanium Grade 5 / 6Al4V Corrosion Resistance

Ti 6Al 4V instantaneously produces a ceramic oxide layer on its surface, which protects it from carrion in all but the most severe of environments. Because of this, grade 5 Titanium is widely used in saltwater applications, as well as humid environments. It is also moderately resistant to highly acid environments though titanium alloys containing palladium are better.

Heat Treatment

Ti 6Al 4V alloy is widely heat-treated to further improve its properties. It is typically mill-annealed, solution-treated treated or aged. Stress relieving is used on formed and welded parts whilst beta annealing is used to improve the alloy’s strength.

Hot Working

Ti 6Al 4V is usually hot-worked in order to produce the desired microstructure through the process of recrystallisation. This keeps the alloys yield strength and hardness low and its ductility high. In grade 5 this is done at approximately 870°C to 980° C which stops the growth of excessive alpha phase.

Cold Working

Ti 6AL 4V is not easily cold-worked due to its low elastic modulus meaning it has a tendency to resume its prior shape. Grade 5 can be cold drawn and extruded though this is typically confined to smaller industrial processing facilities on commercially pure grades of titanium.

Titanium Grade 5 / 6Al4V Machining

 Ti6Al4V parts have good machinability and can be machined as stock parts. The following factors contribute to efficient machining of Ti6Al4V parts: Low cutting speeds, high feed rate, generous quantities of cutting fluid, sharp tools and a rigid setup. You can learn more on our machining page.

Weldability

Ti 6Al-4V can be welded using Ti 6Al-4V as a filler metal. The metal has to be shielded with inert gases to prevent the pickup of oxygen in the weld area which can cause embrittlement and failure. Gas tungsten arc welding is the most commonly used welding process for Ti 6Al-4V alloy, though gas metal arc welding is used for welding thicker sections. Ti 6Al-4V can be successfully welded using plasma arc welding, spot welding, electron beam, laser beam, resistance welding and diffusion welding.

Conclusion

ASTM grade 5 titanium is the most ubiquitous and versatile of titanium alloys. It is comprised of 90% titanium, 6% aluminium and 4% vanadium. It is an alpha-beta titanium alloy with aluminium stabilising the alpha phase and vanadium stabilising the beta phase. Ti 6 Al 4V is widely used because of its optimum blend of properties. It can undergo further processing to become better suited to specific applications.